U.S. patent application number 11/401549 was filed with the patent office on 2006-11-16 for spring arm and body support.
This patent application is currently assigned to Sachtler GmbH & Co. KG. Invention is credited to Dieter Hein, Curt O. Schaller, Roland Seipel.
Application Number | 20060258495 11/401549 |
Document ID | / |
Family ID | 36678349 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060258495 |
Kind Code |
A1 |
Hein; Dieter ; et
al. |
November 16, 2006 |
Spring arm and body support
Abstract
A spring arm (1) for a camera body support is provided with a
parallelogram guide (3, 5) which is made up of two opposing legs
(10, 11) disposed parallel to one another and two likewise opposing
connecting elements (12, 13) that connect the respective ends of
the legs (10, 11) with one another, and an energy storage mechanism
(15), which is supported on two pivot points (17, 19) on the
parallelogram guide (3, 5), in order to compensate a load acting on
the parallelogram guide (3, 5). At least one (19) of these pivot
points (17, 19) is adjustable in relation to the parallelogram
guide (3, 5) such that both the energy storage mechanism's (15)
pretension and also its action of force direction change.
Inventors: |
Hein; Dieter;
(Windach-Hechenwang, DE) ; Schaller; Curt O.;
(Munich, DE) ; Seipel; Roland;
(Gachenbach/Sattelberg, DE) |
Correspondence
Address: |
WOLF GREENFIELD & SACKS, PC
FEDERAL RESERVE PLAZA
600 ATLANTIC AVENUE
BOSTON
MA
02210-2206
US
|
Assignee: |
Sachtler GmbH & Co. KG
Eching
DE
|
Family ID: |
36678349 |
Appl. No.: |
11/401549 |
Filed: |
April 11, 2006 |
Current U.S.
Class: |
474/82 |
Current CPC
Class: |
F16M 11/2014 20130101;
F16M 2200/063 20130101; F16M 2200/044 20130101; F16M 11/2092
20130101; F16M 11/24 20130101; F16M 13/04 20130101 |
Class at
Publication: |
474/082 |
International
Class: |
F16H 59/00 20060101
F16H059/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 15, 2005 |
DE |
10 2005 017 487.6 |
Claims
1. Body support having a spring arm on which a device is to be
mounted, comprising: a parallelogram guide which is made up of two
opposing legs disposed parallel to one another and two likewise
opposing connecting elements that connect the respective ends of
the legs with one another, and an energy storage mechanism, which
is supported on two pivot points on the parallelogram guide, in
order to compensate a load acting on the parallelogram guide, so
that the device is movable through practically its entire range of
movement with the force remaining constant, at least one of these
pivot points being adjustable in relation to the parallelogram
guide that both the energy storage mechanism's pretension and also
its action of force direction change.
2. Body support according to claim 1, in which the at least one
pivot point is adjustable such that both the distance between the
energy storage mechanism's pivot points and also the angle between
a longitudinal axis of the energy storage mechanism and the
direction of the load acting on the parallelogram guide change.
3. Body support according to claim 1, in which a positioning
element is provided which supports the adjustable pivot point on
the parallelogram guide.
4. Body support according to claim 3, in which the positioning
element links the adjustable pivot point with one of the two
connecting elements whilst a fixed pivot point of the energy
storage mechanism is supported on a first leg of the parallelogram
guide.
5. Body support according to claim 3, in which the positioning
element is linearly movable to alter the pretension and the action
of force direction of energy storage mechanism.
6. Body support according to claim 5, in which at least one slot is
provided in the positioning element by way of which it is linked to
the parallelogram guide, whereby the size and shape of this slot
determine the extent of the positioning element's possible
displacement in relation to the parallelogram guide.
7. Body support according to claim 3, in which the positioning
element is movable along a curve to alter the pretension and action
of force direction of the energy storage mechanism.
8. Body support according to claim 1, in which the positioning
element is engaged with a control curve formed in a second leg of
the parallelogram guide such that the angle position and spring
force of the energy storage mechanism are dynamically influenced on
deflection of the parallelogram guide.
9. Body support according to claim 3, in which the positioning
element is movable between a maximum position and a minimum
position, whereby in the maximum position of the positioning
element, a longitudinal axis of the energy storage mechanism forms
a smaller angle with the direction of the load acting on the
parallelogram guide than in the minimum position.
10. Body support according to claim 1, in which the energy storage
mechanism has at least one compression spring.
11. Body support according to claim 1, in which the energy storage
mechanism has at least one tension spring.
12. Body support according to claim 1, in which two parallelogram
guides are present and linked to one another by way of a coupling
element.
13. Body support according to claim 1, further with an attachment,
by way of which it can be attached pivotably to a belt or harness,
and a holder for the attachment of a camera.
Description
TECHNICAL FIELD
[0001] The present invention relates to a body support having a
spring arm according to the preamble of claim 1.
PRIOR ART
[0002] Body supports for cameras with a spring arm have inherently
been known since the mid 70s and have been described for example in
U.S. Pat. Nos. 4,017,168, 4,156,512, 4,208,028 and 4,394,075 as
well as 6,030,130. The spring arm of the body support is fixed on
one of its ends to the cameraman's body by way of a carrying strap,
and the camera is attached on the other end of the spring arm
either simply by way of a camera sled or also by way of a pendulum
system (gimbal). The camera's weight is supported on the
cameraman's body by means of the body support. This makes guiding
the camera considerably easier by comparison with a situation where
the cameraman has to hold the whole weight of the camera in his
hands.
[0003] In this regard the camera's movement is essentially
decoupled from the cameraman's movement. Thus the cameraman can
shoot film whilst walking or even running without his walking or
running movements being transferred to the camera and shaking the
image. Rather the camera floats in space and can easily be tilted
up and down by way of the spring arm as well as panned left and
right around a swivel axis provided on the body support.
[0004] The spring arm of such a body support usually has at least
one parallelogram guide. The camera is then always held in the
horizontal direction on the cameraman's body independently of the
spring arm's position. Often two parallelogram guides are also
joined flexibly together in one spring arm to increase still
further the freedom of movement to guide the camera.
[0005] Furthermore, at least one energy storage mechanism is
present in the spring arm, especially in the form of compression or
tension springs, which is designed such that it compensates as
completely as possible the weight applied by the camera. The known
systems often work with traction cables, deflection pulleys and
tension springs to ensure counterbalancing of the weight in the
spring arm's various positions. Tension springs without Bowden
cable are also used between the parallelogram rods. In this regard,
it may be that shortening and lengthening of the spring element's
pivot points work on tension or compression in which case both
tension springs and also compression springs may be used. Classic
springs, on their own or in conjunction with gas springs, are also
used.
[0006] It should be possible to use such a body support for
different cameras, for example really lightweight video cameras or
also considerably heavier film cameras. It should also be possible
to attach further weights in the form of batteries, monitors, etc.
without impairing the support's performance. Thus it should be
possible to adapt the body support to accommodate different
weights.
[0007] To solve this problem, DE 34 16 823 A1 for example proposes
to adapt the counterforce to the weight of the devices held by
inserting a plurality of compression springs or by removing
compression springs.
[0008] However, regardless of this, the energy storage mechanism
will also vary its spring force on a movement of the parallelogram
guide. Thus, in different positions of the parallelogram guide, the
energy storage mechanism exerts a varying force which may possibly
exceed or fall short of the force exerted by the camera itself. The
cameraman has to absorb this differential force, which leads of
course to impairment of the camera's guidance: often the spring
arm's optimum performance is only generated in the horizontal
position whilst in its very upwardly deflected position the spring
arm only applies an insufficient force. An extreme progression in
the spring arm's lower movement range is also problematic.
[0009] German utility model 83 16 534 describes a spring arm for a
support which likewise has such a parallelogram guide. A gas spring
is provided to relieve the weight. One of the two pivot points of
this gas spring can be moved for precision adjustment of the
counterforce applied by the gas spring such that there is a change
in the angle between the longitudinal axis of this gas spring and
the parallelogram. This adjustment may be stepless or may be made
in steps.
PRESENTATION OF THE INVENTION
[0010] The object of the invention is to create a body support
having a spring arm which exactly compensates the weight of a
device to be held and guided in any position.
[0011] This object is solved with a body support according to claim
1.
[0012] As a result, in a spring arm with a parallelogram guide,
which is made up of two opposing legs disposed parallel to one
another and two likewise opposing connecting elements that connect
the respective ends of said legs with one another, and at least one
energy storage mechanism, which is supported on two pivot points on
the parallelogram guide, in order to compensate a load acting on
said parallelogram guide, at least one of these pivot points is
adjustable in relation to the parallelogram guide such that both
the energy storage mechanism's pretension and its action of force
direction change.
[0013] Therefore, according to the invention, the change in the
energy storage mechanism's action of force direction referred to
above is maintained to influence the energy storage mechanism's
mode of operation. However, the invention provides that said pivot
point of the energy storage mechanism is adjustable in relation to
the parallelogram guide such that in addition the energy storage
mechanism's action of force direction also changes.
[0014] Thus the cameraman can adjust the energy storage mechanism's
adjustable pivot point in any position of the parallelogram guide
such that the energy storage mechanism exactly compensates the
weight of the camera to be guided.
[0015] In this regard the spring arm is designed such that it acts
purely as an energy storage mechanism, thus it evenly provides the
force needed in every position of the parallelogram guide and does
not act with different forces in different positions. The device
guided by means of the parallelogram guide can thus be moved
upwards and downwards through practically its entire range of
movement with the force remaining constant.
[0016] Due to the innovative adjustability of the energy storage
mechanism's pivot points it is also possible to optimize any
kinematics of a parallelogram which have been calculated less than
optimally. In this way it is possible to absorb production errors
and tolerances.
[0017] Advantageous further developments of the spring arm
according to the invention are contained in the dependent
claims.
[0018] Preferably, the at least one pivot point is adjustable such
that there is a change in both the distance between the energy
storage mechanism's pivot points and also the angle between a
longitudinal axis of the energy storage mechanism and the direction
of the load acting on the parallelogram guide.
[0019] A positioning element is preferably provided which supports
the adjustable pivot point on the parallelogram guide in order to
vary the energy storage mechanism's pretension and action of force
direction. The shape of this positioning element is then suitably
calculated such that operating the positioning element changes both
the distance between the spring's pivot points (i.e. the spring
pretension) and also the angle between a longitudinal axis of the
energy storage mechanism and the parallelogram guide (i.e. the
action of force direction).
[0020] For example, the positioning element may link the adjustable
pivot point with one of the two connecting elements whilst a fixed
pivot point of the energy storage mechanism is supported on a leg
of the parallelogram guide.
[0021] The positioning element may be capable of linear movement
for changing the energy storage mechanism's pretension and action
of force direction. Then there can be at least one slot provided in
the positioning element by way of which it is linked to the
parallelogram guide, whereby the size and shape of this slot
determine the extent of the positioning element's possible
displacement in relation to the parallelogram guide.
[0022] Equally, however, it is possible that the positioning
element for altering the pretension and the direction of force
action can be moved along a curve. This may be provided by a curve
or guide rail formed in a second leg of the parallelogram guide in
which a cantilever arm of the positioning element is engaged.
[0023] In either case, the positioning element is preferably
movable between a maximum position and a minimum position whereby,
in the maximum position of the positioning element, a longitudinal
axis of the energy storage mechanism forms a smaller angle with the
direction of the load acting on the parallelogram guide than in the
minimum position. Then the component of the energy storage
mechanism's equalizing force acting against the load is greater in
the maximum position than in the minimum position.
[0024] The energy storage device may have at least one compression
spring which has the advantage that this has a lower progression
behavior due to its characteristics. However, tension spring
arrangements are also possible.
DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 shows an overall view of a first embodiment of the
spring arm according to the invention,
[0026] FIG. 2 shows a parallelogram guide of this spring arm
according to the invention in a top position wherein a positioning
lever is brought into a maximum position.
[0027] FIG. 3 shows this parallelogram guide in the top position
wherein the positioning lever is brought into a minimum
position.
[0028] FIG. 4 shows this parallelogram guide in a bottom position
wherein the positioning lever is brought into the maximum
position.
[0029] FIG. 5 shows this parallelogram guide in the bottom position
wherein the positioning lever is brought into the minimum
position.
[0030] FIG. 6 shows a variation of a parallelogram guide according
to the invention with two compression spring arrangements.
[0031] FIG. 7 shows a variation of a parallelogram guide according
to the invention with tension springs.
[0032] FIG. 8 shows a further variation of a parallelogram guide
according to the invention with compression spring and control
curve.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0033] A first preferred embodiment of a spring arm according to
the invention will now be described with reference to FIGS. 1 to 5
of the drawings.
[0034] FIG. 1 shows an overall view of a spring arm 1 according to
the invention. This consists primarily of two parallelogram guides
3 and 5 which are linked to one another by way of coupling element
7 and which will be discussed in greater detail at a later point.
On its first end, spring arm 1 has a pin 9 by way of which it can
be pivotably attached to a belt or harness of the cameraman. A
holder 31 on the other end of the spring arm serves for attachment
of the camera to be guided.
[0035] The two parallelogram guides 3 and 5 are basically identical
in design. Therefore, only parallelogram 3 is represented in FIGS.
2 to 5; however, all the explanations of it also apply equally to
parallelogram guide 5.
[0036] Parallelogram guide 3 is formed by two opposing legs 10, 11
disposed parallel to one another and two connecting elements 12,
13, which are likewise opposing. First ends of legs 10, 11 are
pivotably attached to connecting element 12 and second ends of legs
10, 11 are pivotably attached to connecting element 13 so that legs
10, 11 and connecting elements 12, 13 form an inherently adjustable
parallelogram. In this regard connecting elements 12, 13 always
remain in a vertical orientation so that a camera attached on the
end of the spring arm is always held in a horizontal position
regardless of the parallelogram's deflection.
[0037] The weight of a camera attached to spring arm 1 (the
direction of the weight is identified in FIG. 1 by the arrow "G")
is compensated in this embodiment by way of a compression spring
arrangement 15. This is housed in a sleeve which supports and
guides compression spring arrangement 15. There is also a
pretensioning mechanism within this sleeve.
[0038] The deflection and angle position of compression spring
arrangement 15 change dynamically during an upward and downward
movement of the camera. Thus the force ratios changing during the
upward and downward movement of the camera are compensated.
[0039] Compression spring arrangement 15 is pivoted at two points
on parallelogram guide 3: in a first pivot point 17, compression
spring arrangement 15 is supported on leg 10 of the parallelogram
guide. This pivot point 17 is not adjustable here in relation to
leg 10 (which could, however, be the case); compression spring
arrangement 15 is merely pivotably disposed around this pivot point
17. In contrast, according to the invention, second pivot point 19
is supported movably on the parallelogram guide.
[0040] In addition, in the embodiment described here, a positioning
element in the form of positioning lever 20 is provided which links
movable pivot point 19 with connecting element 13.
[0041] Here positioning lever 20 has, as an example, two slots 22,
24 through which extend two axes 23, 25 so that positioning lever
20 is supported to be moveable on connecting element 13. The extent
of the displacement of positioning lever 20 in relation to
connecting element 13 is limited by the shape and size of the two
slots 22, 24.
[0042] Actuation of positioning lever 20 by the operator is by
means of an adjusting screw 28 (cf. FIG. 3) which is engaged with a
spindle nut 30 such that spindle nut 30 moves upwards or downwards
on turning adjusting screw 28. Spindle nut 30 for its part is
engaged in a U-shaped driver fork 26 of positioning lever 20 such
that a horizontal movement (i.e. a movement at right angles to
adjusting screw 28) is possible between spindle nut 30 and driver
fork 26.
[0043] The mode of function of positioning lever 20 is best
illustrated by a comparison of FIGS. 2 and 3. In both Figures,
parallelogram guide 3 is shown in the same position, that is, in an
upwardly deflected position. However, in FIG. 2, positioning lever
20 is in a position displaced as far as possible to the top left in
the drawing (maximum position), whilst in FIG. 3 in contrast it is
in a position displaced as far as possible to the bottom right in
the drawing (minimum position).
[0044] First of all, the comparison of FIGS. 2 and 3 shows that
pivot point 19 of compression spring arrangement 15 can be
displaced in relation to parallelogram guide 3 by means of
positioning lever 20--with an unchanged position of parallelogram
guide 3, displacement of positioning lever 20, guided by its slots
22 and 24 and associated axes 23 and 25, causes a displacement of
adjustable or variable pivot point 19 in the direction of arrow A
(=direction of extension of slots 22 and 24) shown in FIGS. 2 and
3. This displacement of pivot point 19 along arrow A has two
effects: firstly, the distance between fixed pivot point 17 and
variable pivot point 19 changes; in the maximum position (FIG. 2)
this distance is greater than in the minimum position (FIG. 3) as a
result of which the pretension of compression spring arrangement 15
changes correspondingly.
[0045] However, at the same time the action of force direction of
compression spring arrangement 15 also changes: the longitudinal
axis of compression spring arrangement 15, identified by "L" in
FIGS. 2 and 3, forms an angle .alpha.2 with the vertical in the
maximum position of positioning lever 20 (FIG. 2) which is smaller
than the corresponding angle .alpha.3 in the minimum position (FIG.
3). The vertical corresponds to the direction in which the weight
of a camera acts on parallelogram guide 3 (cf. FIG. 1). In the
maximum position (FIG. 2), the component of the spring force, which
acts against the weight of the camera directed downwards, is thus
greater than in the minimum position (FIG. 3).
[0046] FIGS. 4 and 5 illustrate a corresponding actuation of
positioning lever 20 from a maximum position (FIG. 4) to a minimum
position (FIG. 5) in a downwardly deflected direction of
parallelogram guide 3. The position of parallelogram guide 3 in
FIGS. 4 and 5 is in turn the same, only the position of variable
pivot point 19 of compression spring arrangement 15 changes by
displacing positioning lever 20 in the direction of arrow A which
is determined by slots 22, 24 and axes 23, 25.
[0047] Here too in the maximum position (FIG. 4), longitudinal axis
L of compression spring arrangement 15 forms a smaller angle
.alpha..sub.4 in relation to the vertical, i.e. relative to the
direction of a camera's weight, than in the minimum position
(.alpha..sub.5, FIG. 5), i.e. the component of the spring force
acting against the weight is greater in the maximum position than
in the minimum position. At the same time, the distance between
fixed 17 and variable pivot point 19 of compression spring
arrangement 15 is smaller in the maximum position (FIG. 4) than in
the minimum position (FIG. 5) with the corresponding effect on the
pretension of compression spring arrangement 15.
[0048] In summary it may be asserted that both the distance between
the two pivot points 17 and 19 and also the angle between
longitudinal axis L of compression spring arrangement 15 change in
relation to parallelogram guide 3 by actuating positioning lever
20. Thus, actuation of positioning lever 20 causes both a change in
the pretension as well as a change in the action of force direction
of compression spring arrangement 15.
[0049] Thus it is possible to adapt the mode of operation of
compression spring arrangement 15 in any position of parallelogram
guide 3 by an appropriate displacement of positioning lever 20 such
that compression spring arrangement 15 exactly compensates the
weight of the camera to be guided.
[0050] Proceeding from the embodiment described above, the
following variations, are conceivable:
[0051] First of all it is possible to combine two compression
spring arrangements in one parallelogram. A parallelogram guide
according to this variation is shown in FIG. 6.
[0052] The two compression spring arrangements 15, 15' lie
mirror-inverted opposite one another in the parallelogram and act
together. Each compression spring arrangement 15, 15' is provided
with its own positioning lever 20, 20' for a movable pivot point
19, 19'. This combination doubles the spring arm's load-bearing
capacity.
[0053] In addition, an embodiment with a tension spring strand of
one to three tension springs is also conceivable. A parallelogram
guide according to this variation is shown in FIG. 7; here three
tension springs 54 are provided. Deflection pulleys 52, 52' of a
parallelogram designed in a "Z-shape" are housed in positioning
elements 20, 20'. Tension springs 54 or rather the cables 56
connecting them run around these curve-shaped variable deflection
pulleys 52, 52'. Pretensioning of the spring strand is achieved
both by way of tensioning screws 50, 50' on the parallelogram's
housing as well as by way of positioning elements 20, 20'.
[0054] As a further variation it is provided that the variable
pivot point is not linearly movable (in the direction of arrow A as
in the embodiment described above with reference to FIGS. 1 to 5)
but moves on a curve on actuation of the positioning element. For
this it would basically be possible, for example, to have openings
corresponding to slots 22 and 24 referred to above which guide
positioning element 20 but which are designed as a curve.
[0055] According to a further development of the invention,
positioning lever 20 is disposed on parallelogram guide 3, 5 such
that its position changes dynamically during the camera's upward
and downward movement. FIG. 8 shows such a parallelogram guide. It
differs from the one discussed above with reference to FIGS. 1 to 5
in that here second leg 11 of the parallelogram acts on positioning
lever 20 and thus there is a continuous specific effect on the
angle position and the spring force of compression spring 15 in
order to exactly compensate a camera's weight in any position of
the parallelogram and to allow the camera to "float" in every
position.
[0056] For this purpose, an element 35 shaped as a curve (control
or pivot curve) is located in second leg 11 of the parallelogram.
Positioning lever 20 (here only partially represented) is connected
to this curve by way of a cantilever arm 40 and travels backwards
and forwards over the curve whilst parallelogram guide 3 moves up
and down. As a result, the position of positioning element 20 is
adapted actively and constantly to the position of the
parallelogram guide.
[0057] Thus the spring performance and progression of compression
spring arrangement 15 can be optimally adapted to the required load
in any position of the parallelogram. The behavior of the
parallelogram required for the application in each case can now be
determined by appropriate selection of pivot curve 35 and spring 15
in respect of their performance, construction and material.
[0058] The manual adjustability of positioning lever 20 described
with reference to the embodiment of FIGS. 1 to 5 may be possible by
way of control curve 35 in addition to dynamically influencing the
position of positioning lever 20.
* * * * *